Fluid lifting system

ABSTRACT

A fluid lifting for a lifting a geological fluid from a formation via a well while limiting environmental impact is provided. The fluid lifting system includes an assembly that is adapted to be raised and lowered within a lift tube by a cable or wire-line. When lowered the assembly traps a predetermined volume of fluid which is then lifted through the lift tube upon raising the assembly. The assembly includes two main components a valve body and a collar which is slidable along the valve body. The valve body includes an axial bore allowing atmospheric air to readily pass through the valve body so as to equalize air pressure across the valve body. The collar includes a fluid passage that is open to fluid flow when the collar is in a raised position along the valve body and which is closed to fluid flow when in a lowered position along the valve body.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to a fluid lift system. More particularly, relating to fluid lift system for lifting a geological fluid, such as water from a formation with reduced environmental impact and sample contamination.

It is desirable to lift a high volume of fluid, such as water from a well for the purpose of sampling and testing the sample for ecological requirements. To get a representative sample for testing, it is necessary to retrieve a volume of water that is equal to three times the volume of water present above the well screen. The sample volume varies from well to well and typically falls within the range of 50 to 1000 liters.

It is critical when lifting the fluid sample from the well not to apply pressure, vacuum, chemicals, aerate or vibrations to the water level of the fluid to prevent changing or damaging the geological formation from which the sample is drawn. Damaging or changing the formation can contaminate the fluid being lifted which can result in false test results during the testing of the sample.

Current fluid lifting systems include submersible pumps, inertial pumps such as the ones available under the name WaTerra Pump, and hand pumps. Submersible pumps are limited by the depth of a well and the retrieval rate or lift rate rapidly drops off with the depth of the pump, they are sensitive to sand and hydrocarbon contents, and tend to be non-durable. WaTerra pumps tend to have a problem with lift tube bending, create vibrations and have a low retrieval rate. Hand pumps while do not have a depth limit they are difficult to operate, have a very low retrieval rate and include the danger of being dropped into the well.

In addition, current water sampling standards are becoming much more labor intensive requiring more frequent sampling and sampling from deeper wells. Therefore, a need exists for a new and improved fluid lifting system that has a higher rater of retrieval, includes no driven mechanical elements, is easy to operate, does not impact the formation and which is not well depth limited. In this regard, the present invention substantially fulfills this need.

SUMMARY OF THE INVENTION

In accordance with the present invention, an apparatus for a lifting a geological fluid from a formation via a well while limiting environmental impact is provided.

The apparatus essentially comprises an assembly that is adapted to be raised and lowered within a lift tube by a cable or wire-line. When lowered the assembly traps a predetermined volume of fluid which is then lifted through the lift tube upon raising the assembly. The assembly includes two main components a valve body and a collar which is slidable along the valve body. The valve body includes an axial bore allowing atmospheric air to readily pass through the valve body so as to equalize air pressure across the valve body. The collar includes a fluid passage that is open to fluid flow when the collar is in a raised position along the valve body and which is closed to fluid flow when in a lowered position along the valve body. In addition, the collar makes a fluid tight engagement with the lift tube.

In operation, the assembly is lowered down the lift tube and into a column of fluid, such as water present above the well screen. Upon lowering the assembly into the column of water, the collar is raised along the valve body thereby allowing a volume of water to readily pass through the collar and collect within a trap zone. Once the assembly has been lowered to a desired depth, the collar slides down along the valve body by under the force of gravity to a point where the fluid passage is closed. The assembly is then raised lifting the volume of water contained within the trap zone. Upon lifting, air is readily passed through the axial bore of the valve body equalizing pressure across the valve body to eliminate creating a vacuum between the assembly and the column of water remaining in the lift tube. The column of water contained in the trap zone applies a downward pressure on the collar thereby increasing the seal of the fluid passage preventing water from draining back through the fluid passage and into the remaining water in the formation. The assembly is raised to height where the water contained within the trap zone is drawn off into a collection container and then is lowered down the lift tube to collect an additional volume of water from the formation. This process is repeated until the desired quantity of water is retrieved from the well.

There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.

Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1 is a side elevation view of a preferred embodiment of the fluid lifting system constructed in accordance with the principles of the present invention in use.

FIG. 2 illustrates the fluid lifting system in a partially lowered position.

FIG. 3 illustrates the fluid lifting system in a fully lowered position.

FIG. 4 illustrates the fluid lifting system in a partially raised position subsequent to the fully lowered position illustrated in FIG. 3.

FIG. 5 illustrates the fluid lifting in an intermediate raised position subsequent to the position illustrated in FIG. 4.

FIG. 6 illustrates the fluid lifting system in a fully raised position.

The same reference numerals refer to the same parts throughout the various figures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and particularly to FIGS. 1-6, a preferred embodiment of the fluid lift system of the present invention is shown and generally designated by the reference numeral 10.

In FIG. 1, a new and improved fluid lift system 10 of the present invention for lifting a fluid, such as water from a geological formation is illustrated and will be described. More particularly, the fluid lift system 10 includes a lift assembly 12 that is adapted to be raised and lowered within a lift tube 14 by a cable or wire-line 16.

The lift assembly 12 includes a valve body 18 having a first end 20 and a second end 22 and a collar 24 slidable along a section of the valve body intermediate ends 20 and 22. The valve body 18 further defines an axial bore 26 extending therethrough from the first end 20 to the second end 22. Fluid, air or liquid is free to flow either in an upwardly or downwardly direction through the axial bore 26 for the purpose of equalizing pressure across the valve body 18. The collar 24 includes a fluid passage 28 which is open to readily pass fluid therethrough when the collar is in a raised position on the valve body 18 and which is sealed when the collar is in a lowered position on the valve body.

The collar 24 is restrained to slide along the valve body 18 a predetermined stroke which has an upper limit and a lower limit. The upper and lower limits are defined by an upper stop 30 and a lower stop 32. Preferably, the upper stop 30 is a radial flange extending from the surface of the valve body 18 and the lower stop 32 is shoulder extending from the valve body. Most preferably, the shouldered 32 is a tapered shoulder. Even more preferably, the taper is in a downward direction. When the collar 24 is in the lower limit position along the valve body 18, the fluid passage 28 is sealed preventing fluid flow therethrough by the shoulder 32. As the collar 24 is raised from the shoulder 32, the fluid passage 28 is opened to fluid flow.

While the collar 24 is free to reciprocate a predetermined stroke along the valve body 18, the perimeter of the collar is engaged with the lift tube 16 making a fluid seal therewith. The fluid seal between the collar 24 and the lift tube 16 ensures all fluid passing by the collar must pass through the fluid passage 28, which is controlled based upon the position of the collar along the valve body 18.

The first end 20 of the valve body, an upper surface 34 of the collar 24 and the annulus of the lift tube above the shoulder 32 defines a trap zone 36. Preferably, a conduit 38 is attached to the first end 20 of the valve body extending the height trap zone 36 above the shoulder 32. The conduit 38 can be sized to tailor the volume of the trap zone 36 for a particular application. The conduit 38 is attached to the first end 20 of the valve body 18 so that the conduit and the axial bore 26 of the valve body are in fluid communication so that air or fluid passing therethrough can also freely enter the conduit.

Referring now to FIG. 2, the lift assembly 12 is illustrated in an intermediate lowered position in the lift tube 14, where the lift assembly is partially lowered into a column of formation water 40 contained within the lift tube. In this intermediate position, the collar 24 is in a raised position allowing a quantity of water from the water column 40 to pass through the fluid passage 28 and into the trap zone 36, and a quantity of water from the water column enters the axial bore 26 and conduit 38 to equalize pressure across the valve body to prevent compressive forces from being applied to the water column. Collar 24 is designed to have a slower sinking rate then that of the valve body 18 so as to raise the collar 24 along the valve body during the initial lowering of the lift assembly 12 into the water column 40.

Turning now to FIG. 3, the lift assembly 12 is completed lowered to a desired depth down the lift tube 14 and into the water column 40. Preferably, the lift assembly 12 is lowered to a depth so that the upper surface 34 of the collar is at the same depth as the top of the well screen 42. At this point, the collar 24 has been allowed to sink until its lowest most point where the fluid passage 28 is sealed. Preferably, the passage 28 is sealed by engagement of the collar 18 with the shoulder 32. In addition at this point, the maximum volume of water entering the trap zone 36 from the water column 40 is contained within the trap zone and pressure across the valve body 18 is equalized.

Referring now to FIG. 4, the lift assembly 12 is illustrated partially raised from the water column 40. During this period, first a hydrostatic pressure created by the volume of water contained within the trap zone 36 is applied to the upper surface 34 of the collar 24 increasing the sealing of the fluid passage 28 by increasing the contact pressure between the shoulder 32 and the collar. Second, atmospheric air present within the lift tube 14 is pulled through the conduit 38 into the axial bore 26 of the valve body 18 by a differential pressure present within the axial bore created by water within the water column 40 flowing downwardly through the axial bore. As atmospheric air continues to enter the axial bore 26 a vacuum is prevented from occurring between the lift assembly 12 and the water column 40. The flow of air is indicated by the open arrows and the flow of water is indicated by the filled arrows. This equalization of pressure across the valve body 18 during raising thereof is critical to the operation of the fluid lift system 10.

FIG. 5 illustrates the lift assembly 12 completely raised from the water column 40, where atmospheric air continues to travel through the valve body 18 to ensure a vacuum is not created between the lift assembly and the water column 40. As the lift assembly 12 is continually raised in the lift tube 14 the water contained within the trap zone 36 is drawn off and out of the lift tube, as illustrated in FIG. 6.

Once the water is completely drawn off from the trap zone 36, the lift assembly 12 is lowered back down the lift tube 14 where the complete lift cycle begins once again. This process can be repeated a number of times until a desired volume of water is retrieved from the well. Preferably, the volume retrieved from the well is equal to three times the volume of water in the water column 40 present above the well screen 42.

A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims. 

1. A fluid lifting system comprising: a valve body adapted to be raised and lowered within a lift tube, said valve body defining an axial bore, said axial bore allowing fluid to freely flow through said valve body; a collar slidably received by said valve body, said collar defining at least one fluid passage passing therethrough, wherein said fluid passage is open allowing fluid flow therethrough when said collar is in a raised position on said valve body and said fluid passage is closed preventing fluid flow therethrough when said collar is in a lowered position on said valve body; and a lift cable attached to said valve body.
 2. The fluid lifting system of claim 1, further comprising: a conduit attached to and extending upwardly from said valve body and in fluid communication with said axial bore defined by said valve body.
 3. The fluid lifting system of claim 1, wherein said lift tube defines a sand screen.
 4. The fluid lifting system of claim 1, wherein said collar contacts said lift tube and creates a fluid tight seal therewith.
 5. A ground water lifting system comprising: a valve body slidably positioned within a lift tube, said valve body defining an axial bore, said axial bore allowing the equalization of fluid pressure across said valve body; a collar mounted to said valve body so as to allow said collar to reciprocate a predetermined stroke along a section of said valve body, said collar defining at least one fluid passage extending therethrough, wherein said fluid passage is closed to fluid flow when said collar is at its lowest most point in said stroke, said collar defining a fluid tight seal with said lift tube; and a lift cable, said lift attached to said valve body for raising and lowering said valve body within said lift tube.
 6. The ground water lifting system of claim 5, wherein said valve body defines a lower stop and an upper stop at a spaced distance from said lower stop, said upper stop defining an upper limit of said stroke and said lower stop defining a lower limit of said stroke.
 7. The ground water lifting system of claim 6, wherein said lower stop is a shoulder which engages said collar when said collar is at said lower limit and which seals said at least one fluid passage defined by said collar.
 8. The ground water lifting system of claim 7, wherein said shoulder is a tapered shoulder.
 9. The ground water lifting system of claim 5, further comprising a conduit attached to and extending upwardly from said valve body and in fluid communication with said axially bore thereof.
 10. The ground water lifting system of claim 5, wherein said lift tube defines a sand screen along a section of said lift tube.
 11. The ground water lifting system of claim 5, wherein said collar sinks at a slower rate then said valve body when said valve body and said collar are lowered into a column of fluid contained within said lift tube. 